TEINEMA LINEARE. 93 



sub-circular ; aperture circular, oblique, invaginated ; 

 plasma colourless, granular, partly filling the test; 

 nucleus containing a single nucleole, placed posteriorly ; 

 two contractile vesicles usually present ; pseudopodia 

 long, attenuate, radiating, usually one to three in 

 number. 



Length 18-35 /a; breadth 7-1 7 ju.; aperture 3-6)u,; 

 scales 3-6 ju, in diameter. 



Habitat. — Mosses, sphagnum, and aquatic vegetation. 



Grenerally distributed. 



This small species is even more common than the 

 preceding ; scarcely a tuft of moss can be found which 

 does not contain numerous individuals. 



Fig. 153. — Outlines of tests of Trinema lineare showing angle of 

 aperture varying from normal (a) to terminal (/), and abnormal 

 evaginated aperture {g). x 650. 



The curvature of the small scales forming the test 

 is generally such as to present a continuous outline, 

 but they may be convex, flat, or, rarely, slightly 

 concave. The angle at which the aperture is placed 

 varies more frequently in this species than in T. 

 enclielys ; while 30° is the normal angle between the 

 plane of the aperture and the longitudinal axis of the 

 test, every variety of inclination between this and 

 90°, or a terminal aperture, may occur. Abnormal 

 evaginated apertures are also occasionally found. 



In structure the test is similar to that of T. enchelys, 

 but owing to its small size and extreme transparency 

 the details can seldom be distinguished without special 

 preparation and the use of a high magnification. 



Conjugating individuals are not uncommon. Prom 

 T. enchdys, the only species with which it is likely to 



